Aspirator and method of making the same



y 1941 w. E. WHITNE'Y 8,

ASPIRATOR AND METHOD OF MAKING THE SAME Filed Nov. 25, 1939 2 Sheets-Sheet 1 :l 7 E E 7 9 ,3 4 1 1 6 l 4/ j E Q July 8, 1941. w. E. WHITNEY ASPIRATOR AND METHOD OF MAKING THE SAME Filed NOV. 25, 1939 2 Sheets-Sheet 2 Patented July 8, 1941 UNIT-eo- Q rFFlCE 2,218,261 ASPIEAT-GR*ANDMETHOD*'OFMAKING"THE -WilliamrE. .W'hitney, Cambridga: Mass, assignor, Lby mesnefassignments, t0L'StatorIGorporation a v corporation. of Rhode Island :"ApplicatiomNovember 25, 1939,?vSerial fNo. 3'06;058'

'4 Claims. (01; 230-95) This invention I'relate's. totimproved .aspirator mixing chambers midi-to a method ofiimakingz a preferred form. of mixingcchanrber. v

When aspirators are employed inrpermanent'ly arrange the outer wall 'of' the mixing chamber as well- -as' the' end -wall thereof so that the-metal grain -extends-substantially in the plane of the corresponding "walk-portion rather than extendsealed systems which shouldxmaintai'nsoperating :5 ing transversely ofthesame. Such'an' arrangeefiiciencyfor'a long 'period offtime 'withoutrre- "ment'avoids the-"slight porosity that otherwise q r t i "it" is 'h 'hlyfdesirable' to conwouldybe'likely -to be-*present-; in the aspirat'or struct the-aspirator or aspirat'ors 'so thatrleakage mixing chamber arid-which might ultimately through the walls thereofisfiavoided; *Forexamresult in the"leakage of an--- appreciable quantity ple, in the case of refrigerating system'si'such as 71 0 of 'gas' into the 'seald' system. disclosed in the copending'applica-tionof Lyman In ithe aeoompanying; drawings, F. Whitney, Serial No. 1 771749,:fiIed'December 'Eig. l' is a central-vertical section of a mixing 1937, it is desirable to arrangeallparts of the cliamber and' adjoining parts; -showing such a system, including the aspirator'mixing-chambers, "mixing 'chamber constructed in-accordance with so that leakageof atmosphericrairxinto the'systhe present invention; v

tem is practically precluded; System's: of this Fig. 2: i's a similar View of' an optional form of character may operate atfrelatively: lowipresmixingfichamb'er andadjoining parts;

sures; forexample, pressuresiofxonlyiailfewmilli- Fig. 3-is an isometric 'part of a metal plate meters of mercury absolute mayprevailzin'the which-maybe employed tomake the body of aspirator heads. The leakagexofiair'into'suchia:20 th rnjxin'gtchambershown in 'Fig 1;

system, even at a slow rate, might seriously impair operating efii'ciency:

In general, the parts of the system. are'constructed of elementssuch assteeltubinggwhich may be welded. together substanti'ally to 'preclude inward leakage of atmo'spheric'air. I have discovered, however, that conventional forged or cast aspirator' mixing chambers;.although praotically impervious to the -passage df-= gas, *Wl'll,

overa relatively long: period of timepper-mit the nels or flow lines in t'he metal'extendingithrough I the walls'of the head.

In the preferred embodimentiof the invention, I provide a. forging formed of" an original: plate or metal part, with themetal-grain 'soidisposed both in the original metal part and in thersulti' mate forging that even slightrleakage through the latter is substantially precluded=when the forging is assembled with cooperatingi-partsto afford an aspirator.mixing-chamber; Furthermore, a forging of this type may afford aniadvantageous shape for the mixing:chamber to facilitate relatively high operating efficiency. j

I have also found thataa .similar result may be attained, in: so far as-cleakage is concerned, by buildingup an aspirator'mixing'ohamberout of plate-sectiona-a .ring se-otionwancltthe :like', eachsection having the metal grain: thereofiidis posed in a general manner. corresponding.- to that of the metal :grain in-the: forged mixing-"chamber. In any: case, I have-rfounduit advantageous to V @Figsfiand 5' are'sectional views -on planes at right angles to each other and showing an intermediate forging formed' of the metal plate shown in Fi'g. 3;an'd

'Figrfiishows the final form-of the forging'made thex' late of Fig. 3.

Fig. 1 shows the mixing chamber and adjoining p'arts of an aspirator of the general type disclosed -in"the* ab'ove' mentioned application of Liyman F. Whitney. Such an aspirator is -provide'd; for example; with a" propellant supply tiibe l 'from which propellantvapor; such as mercury-vapor, passes through an aspirato'r nozzle 2 into a mixing chamber; designated generally "by" the 'num'eral 3. "Aibraeket, designated by numeral 4, :holdsf'themozzl'e 2 in" alignment with an a'sp'irat'or funnel T6, the latter b'eing' 'surrounded by cooling fins 1'..disp0sed='within a' jacket'B'; T-he mixing chamberm'ay'comprise a domed head l 0 0i relatively thimnretal, this head being' formed by dishing ai platefiimsucha 'manner that theme'tal grain in each section of"thehead lies substantially'inrthe*plane*of' that' section. lThe nozzle z extends through the head. Theiremainder -o'f the "mixing chamber 'may' be' providedfiby a forg mg l 4' providing an. outerannular wall 'l and an inner' end ==wal1 l 6' into which the end of the tubular? aspirator-funriehfits in alignment :with nozzle 2. The head l-il is"welded-to the annular wall I 5: The 'forgingM also provides anianmilar flange t8 whieh::is"provided with arabbet to receive'the'encrof the ijacketmemberi or-isle'eve 8.

In accordance"- with" the presentcinvehtion the forging is 'preferably provided with the intal grain: in1- each apart: thereof preponrierantlyf extending in the direction of the inner surface of the corresponding section of the wall rather than transversely of the same. Thus the forging as well as the dished head may be substantially free of flow lines or minute passages extending transversely to adjoining inner surfaces of the chamber. Thus Fig. 6 shows the forging I4 before the same has been assembled with the other parts of the aspirator, the position of the light lines indicating the preponderan-t direction of the metal grain. It will be noted that the intermediate part of the wall 16 is provided with an inwardly tapered surface to be disposed about the end of the funnel 6. The inner surface of the outer wall of the forging is preferably machined before assembly with the rest of the mix-.

ing chamber. This general form of forging I have found particularly conducive to aspirating efficiency while also entirely consistent with good forging practice.

Figs. 3 to 6 indicate how a forging of the type shown in Fig. 1 may be formed with its metal grain or flow lines so disposed as to avoid the slight porosity characterizing ordinary forgings, which might be objectionable in sealed apparatus of the character referred to herein. The forging may be formed from a flat plate or piece of stock 20 which has been so prepared by rolling or otherwise that the direction of its metal grain is substantially parallel to its planar surfaces. Such a plate may be heated and then hot pressed between suitable dies to give a cuplike form, such as shown in Figs. 4' and 5, which are sections at right angles to each other. The light lines in Fig. 4 show the direction of the flow lines or metal grain, while in Fig. 5 the light dotsshow how the metal grain is'cut by this sectional view. A final hot forging operation with suitable dies "may then-be'effective in forming-the member M'which is'shown in Fig. 6, it beingeevidenit that the metal grain 'in the central portion of the forging extends parallel to the upper surface of this part of the forging as viewed in Fig. 6, that the grain of the beveled surface surrounding this central portion is correspondingly parallel to such beveled surface, and that the grain in the outer annular wall is substantially parallel to the inner surface of that wall. At the outer part of the forging and at the part thereof which is to receive the jacket sleeve 8, the metal grain may extend-in the directions shown in Fig. 6, these portions of the forging not being important in so far as leakage from the mixing chamber is concerned.

Some of the advantages of the arrangement shown in Fig. 1 can also be obtained with an assembly of the type shown in Fig. 2. This assembly comprises a propellant supply durct l, a nozzle 2, and a bracket 4 similar to those previously described. A head H9, corresponding to the head 10, is also provided for the mixing chamber I03. The outer wall of this chamber is, however, afforded by a small ring section H5 with the grain of the metalextenlding parallel to the inner surface portions of the corresponding parts of the ring. Such a ring may conveniently be provided by cutting a short section from a tube, it being well recognized that tubular stock generally has its metal grain extending parallel to the longitudinal axis of the tube. The inner wall H6 of the .head may be formed of a plate having its metal grain parallel to its planar surfaces. The plate is cut to provide a disk that may be welded to the member H5, the latter in turn being welded to the head IN). A

second ring section H8 may be welded to the disk I03 to provide a member for connection to the jacket sleeve of the aspirator.

It will of course be understood that the annular outer wall of the mixing chamber shown in Fig. 1 or the corresponding wall of the chamber shown in Fig. 2 may be cut away as by a drill to afford a suitable opening and a vapor supply pipe may be Welded to the wall about this opening to permit the flow of vapor, such as refrigerant vapor, into the mixing chamber. For example, the detailed structural arrangement of the connection of the vapor duct to the outer wall of the mixing chamber is shown in the above-identified Whitney application.

In general, an aspirator head formed as shown in Fig. 2 approximates the resistance to leakage that is permitted bya head of the type shown in Fig. 1. I, however, prefer a head such as shown in Fig. 1 formed from a forging wherein the metal particles have been compacted under heat and pressure. Furthermore, $111611 2, member may readily be shaped to facilitate high aspirating efficiency.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I'claim:

1. An aspirator comprising a nozzle, a funnel aligned with the nozzle, a mixing chamber between the funnel and nozzle and connected thereto, said mixing chamber having a head through which the nozzle may supply propellant vapor, said mixing chamber also having an inner end wall and an outer annular wall both provided by a single forging, the inner end wall providing a central opening where the funnel is connected thereto and being beveled about said opening, the forging being characterized by metal-grain structure pr'eponderantly paralleling the inner surfaces of adjoining wall portions. and being substantially free of pores and flow lines extending transversely to said surfaces.

'2. An aspirator comprising a nozzle, a funnel aligned with the nozzle, a mixing chamber between the funnel and nozzle and connected thereto, said mixing chamber having a head through which the nozzle may supply propellant vapor, said mixing chamber also having an inner end wall and an outer annular wall both provided by a single forging, the inner end wall providing an opening where the funnel is connected thereto, the forging being characterized by metal grain structure which preponderantly parallels the inner surfaces of adjoining wall portions and which is substantially free of pores and flow lines extending transversely to said surfaces.

3. An aspirator comprising a nozzle. a funnel aligned with the nozzle, a mixing chamber between the funnel and nozzle and connected thereto, said mixing chamber having a head through which the nozzle may supply propellant vapor, said mixing chamber also having an inner end wall and an outer annular metal wall, the inner end wall providing an opening where the funnel is connected thereto, the metal of the outer wall being characterized by grain structure which preponderantly parallels the inner surfaces of adjoining portions of said outer wall and which is substantially free of pores and flow lines extending transversely to said surfaces.

4. An aspirator comprising a nozzle, a funnel aligned with the nozzle, a mixing chamber between the funnel and nozzle and connected thereto, said mixing chamber having a head through which the nozzle may supply propellant vapor, said mixing chamber also having a metal inner end wall and an outer annular Wall between the head and the inner wall, said inner end wall providing an opening where the funnel is connected thereto, the metal of said inner wall being characterized by metal grain structure which preponderantly parallels the inner surfaces of adjoining portions of said inner wall and which is substantially free of pores and flow lines extending transversely to said surfaces.

WILLIAM E. WHITNEY. 

